Protective suit fabric and spun yarn used for the same

Abstract

A protective suit fabric of the present invention is a heat-resistant flame-retardant protective suit fabric, which is formed of a spun yarn. The fiber blend rate is: 25-75 mass % of polyetherimide fiber (A); 20-50 mass % of at least one fiber (B) selected from wool and flame-retardant rayon; and 5 to 25 mass % of para-aramid fiber (C). The spun yarn for forming the fabric is a two-fold yarn ( 20 ) prepared by twisting: 1) a single yarn ( 24 ) of a uniform blended spun yarn including the fiber components (A) and (B); and 2) a single yarn ( 23 ) of a sheath-core spun yarn including a core ( 21 ) of stretch-broken spun yarn of the para-aramid fiber (C) and a sheath ( 22 ) formed by blend-spinning the polyetherimide fiber (A) and the at least one fiber (B) selected from wool and flame-retardant rayon. The protective suit fabric has high washing resistance. The protective suit fabric provides favorable comfort in wearing even if the suit is worn in the hot seasons or even if the wearer perspires during exertion. The fabric has high heat resistance and high flame retardance, favorable dye affinity, and the fabric can be produced at a low cost. Also a spun yarn used for the fabric is provided.

1 . A heat-resistant flame-retardant protective suit fabric formed of a spun yarn of blended fibers comprising: 25 to 75 mass % of polyetherimide fiber (A); 20 to 50 mass % of at least one fiber (B) selected from wool and flame-retardant rayon; and 5 to 25 mass % of para-aramid fiber (C) when the fabric is formed of 100 mass % of fibers,
 wherein the spun yarn for forming the fabric is a two-fold yarn prepared by twisting 1) a single yarn of a uniform blended spun yarn comprising the fiber components (A) and (B); and 2) a single yarn of a sheath-core spun yarn comprising a core of a yarn of a stretch-broken para-aramid fiber (C) and a sheath formed by blend-spinning the polyetherimide fiber (A) and the at least one fiber (B) selected from wool and flame-retardant rayon.   
     
     
         2 . The protective suit fabric according to  claim 1 , wherein a twist factor Ks 1  of the single yarn of the uniform blended spun yarn is in a range of 2560-2750, the two-fold yarn is twisted in a direction opposite to the direction for twisting the single yarn, and a twist factor Ks 2  of the two-fold yarn is in a range of 3490 to 3760,
 where the twist factor Ks 1  of the single yarn and the twist factor Ks 2  of the two-fold yarn are calculated by equations below:
     Ks   1   =T   1   ·√S   1    
     Ks   2   =T   2   ·√S   2    
   in the equations, T 1  indicates a twist number (time/m) of the single yarn, T 2  indicates a twist number (time/m) of the two-fold yarn, S 1  indicates a single yarn fineness (tex) and S 2  indicates a two-fold yarn fineness (tex).   
     
     
         3 . The protective suit fabric according to  claim 1 , which experiences no heat shrinkage when exposed to a heat flux at 80 kW/m 2 ±5% for 3 seconds in accordance with ISO 9151 Determination of Heat Transmission on Exposure to Flame and which has a char length of not more than 5 cm in the longitudinal and horizontal directions in the flammability test specified in JIS L 1091A-4. 
     
     
         4 . The protective suit fabric according to  claim 1 , wherein the blended spun yarn further comprises an antistatic fiber. 
     
     
         5 . The protective suit fabric according to  claim 1 , which is either a woven fabric or a knitted fabric. 
     
     
         6 . The protective suit fabric according to  claim 1 , wherein the polyetherimide fiber that forms the protective suit fabric has been dyed as a fiber, as a yarn or as a fabric, and the para-aramid fiber has been spun-dyed. 
     
     
         7 . The protective suit fabric according to  claim 1 , wherein the mass per unit of the protective suit fabric is in a range of 100 to 340 g/m 2 . 
     
     
         8 . A heat-resistant flame-retardant spun yarn, comprising fibers at a blend rate of: 25 to 75 mass % of polyetherimide fiber (A); 20 to 50 mass % of at least one fiber (B) selected from wool and flame-retardant rayon; and 5 to 25 mass % of para-aramid fiber (C) when the spun yarn is formed of 100 mass % of fibers, and
 the spun yarn is a two-fold yarn prepared by twisting: 1) a single yarn of a uniform blended spun yarn comprising the fiber components (A) and (B); and 2) a single yarn of a sheath-core spun yarn comprising a core of a yarn of a stretch-broken para-aramid fiber (C) and a sheath formed by blend-spinning the polyetherimide fiber (A) and the at least one fiber (B) selected from wool and flame-retardant rayon.   
     
     
         9 . The spun yarn according to  claim 8 , which is formed of a two-fold yarn, and a twist factor Ks 1  of the single yarn is in a range of 2560 to 2750, the two-fold yarn is twisted in a direction opposite to the direction for twisting the single yarn and a twist factor Ks 2  of the two-fold yarn is in a range of 3490 to 3760,
 where the twist factor Ks 1  of the single yarn and the twist factor Ks 2  of the two-fold yarn are calculated by equations below:
     Ks   1   =T   1   ·√S   1    
     Ks   2   =T   2   ·√S   2    
   in the equations, T 1  indicates a twist number (time/m) of the single yarn, T 2  indicates a twist number (time/m) of the two-fold yarn, S 1  indicates a single yarn fineness (tex) and S 2  indicates a two-fold yarn fineness (tex).   
     
     
         10 . The spun yarn according to  claim 8 , wherein the blended spun yarn further comprises an antistatic fiber. 
     
     
         11 . The spun yarn according to  claim 10 , wherein the content of the antistatic fiber is in a range of 0.1 to 1 mass %.